April 5, 2010By JEREMY OLSHANThis crew is a bit clownish even by bridge-and-tunnel standards.A group of unicyclists is determined to pedal across the bridges of New York City -- and not just landmarks like the Brooklyn, 59th Street and Manhattan -- but all 2,078 of them.They are doing it, in part, for the glory and the absurdity, says artist and group member Rob Hickman, but mostly in the belief that unicycles can unite the disparate corners of the city just as its bridges do."A lot of people don't like bicyclists and bicycle politics, but everyone loves a unicycle," Hickman said."We even went down Bedford Avenue in Williamsburg where the Hasidic community rallied to have bike lanes removed, and they loved us there."Beginning their journey last October, Hickman and his pedal partner, Keith Nelson, have crossed 50 spans so far, starting with the Williamsburg Bridge.Last week, they hit the Cropsey and Stillwell avenue bridges in Coney Island, maintaining their usual pace of 6 to 10 mph."Many of these are architectural masterpieces and some, well, aren't," said Nelson, who has been documenting the journey on his blog, Unicycle NYC Bridge Tour. "But we take a photo at the middle of every bridge and try not to pick favorites."Riding a unicycle in city traffic and on shaking bridges can be harrowing."The Bayonne Bridge, that was rough," Nelson said. "We have one or two unexpected comings-off per ride -- but, generally, you land on your feet."But New Yorkers can be a tough audience, Nelson said."The No. 1 question we get is, 'Do you also juggle?' " he said.Many of the spans feature steep inclines, which presents challenges in both directions."Uphill is physically more strenuous, but not by much," Nelson said. "Mentally, downhill is much harder -- holding back momentum is just not easy."The bridge-crossing rides -- which all end at a bar -- have grown longer as the group prepares to participate in the Five Borough Bike Tour."That's the only way we can legally cross the Verrazano Bridge, but we'll have to ride 40 miles to get there," he said.The group says it has no idea how long it will take to complete its mission."But once we're done, we can move on to the overpasses of the BQE," Hickman said.jeremy.olshan@nypost.com